<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>06_CSS外间距测距</title>
    <style>
        body {
            margin: 0px;
        }

        * {
            margin: 0px;
            padding: 0px;
        }
    </style>
</head>
<body>
<div class="fu">
    <div class="z1">子元素1</div>
    <div class="z2">子元素2</div>
    <div class="z3">子元素3</div>
    <div class="z4">子元素4</div>
</div>
</body>
</html>